(a) Field of the Invention
The present invention relates generally to a mother plate for a flexible printed circuit film with a cutting mark and a display device made with a flexible printed circuit film cut from the mother plate, and more particularly to a mother plate for a flexible printed circuit film that is easy to cut and a display device provided with the flexible printed circuit film.
(b) Description of the Related Art
Due to the recent development of semiconductor technologies, the demand for display devices of small size, light weight, and high performance has increased explosively. Naturally, liquid crystal display (LCD) devices, which have the desired characteristics of small size, light weight, and low power consumption, have been receiving much attention as a substitute for cathode ray tubes (CRTs). Today, LCD devices are widely used for all types of data processing systems that require a display device.
Generally, an LCD device is a display device that displays information through light modulation. Light modulation is achieved by changing the alignments of liquid crystal molecules, which in turn is done by adjusting the applied voltage. Adjustment of the voltage that is applied to the liquid crystal molecules causes changes in the liquid crystals' optical characteristics such as birefringence, optical rotary power, dichroism, and optical scattering, all of which translate to a visual change.
Such LCD devices are used for most flat display devices, like cellular phones, monitors, TVs, etc., and as rapid technological developments have been made, they have become available with higher definition, lighter weight, and thinner shape than before.
The technological development of the LCD devices is accompanied by progress in the thin film transistor (TFT) technology, driver integrated circuit (IC) chip, and flexible printed circuit film as an electrical connection member capable of micropitching.
A flexible printed circuit film of the LCD device can be interposed between an LCD panel and a circuit unit to connect them. The flexible printed circuit film with a driver IC chip is used for COF (chip on film), TCT (tape carrier package), etc.
When the flexible printed circuit film is connected with other elements, it is important for the connecting portion to stay securely closed. If the connecting portion opens, it causes reduction of device life span or malfunction. However, in conventional LCD devices, there were many cases where the panel with the thin film transistors and the flexible printed circuit film are not properly connected, causing the connection to open. The open connecting portion erodes, causing a malfunction of the product. Such an open connecting portion occurs when the electrode terminal of the flexible printed circuit film corresponding to the connecting portion is not properly cut during the manufacturing of the flexible printed circuit film. If the flexible printed circuit film is connected to the electrode in an improperly cut state, a gap will form. If the gap is detected after the flexible printed circuit film is connected to the LCD panel, the product defect rate is increased.
Accordingly, manufacturing high-quality flexible printed circuit film directly improves the quality of the display device. Precise, gapless connection between the flexible printed circuit film and the electrode terminal of the display device is also desired for improving display device quality.